There is a growing trend in the automobile industry to use internally adjustable reflector headlamps. Internally adjustable reflector headlamps include a reflector and bulb socket assembly enclosed within a sealed headlamp housing and lens. The orientation of the reflector within the housing is adjustable to control the direction of the light beam cast by the headlamp. Typically, the adjustable reflector is supported by three ball studs that extend from the rear of the headlamp housing and fit within sockets located in three corners of the reflector. The middle ball stud is secured directly to the headlamp housing to provide a fixed pivot point for the reflector. The other two ball studs are connected to a pair adjuster mechanisms secured to the rear of the headlamp housing. By operating the adjuster mechanisms, these two ball studs can be extended and retracted to control the horizontal and vertical orientation of the reflector. Examples of such adjusters include those disclosed in U.S. Pat. Nos. 5,707,133 and 5,214,971 to Burtoll et al., 5,483,426 to Lewis et al., 4,796,494 to Eckenrode et al., and 4,703,399 to Van Duyn et al.
Recent changes in the United States National Highway Traffic Safety Administration ("NHTSA") standards require that horizontal adjuster mechanisms used in connection with internally adjustable reflector headlamps must be either non-readjustable after the proper aim has been achieved or be equipped with a non-recalibratable vehicle headlamp aiming device ("VHAD") which is zeroed after the proper aim has been achieved. Previously, recalibration of the VHAD was allowable under the NHTSA standards. As such, vehicle manufacturers must either aim the lamps and provide a mechanism to prevent future readjustment or aim the lamps and provide a non-recalibratable VHAD which is properly zeroed. Examples of adjusters which include VHADs that can be recalibrated are disclosed in U.S. Pat. Nos. 5,622,421 and 5,539,625 to Turley, Jr. et al. and U.S. Pat. No. 5,446,632 to Childs et al. However, because ofthe change in NHTSA standards, the devices disclosed in the above patents can no longer be used in the manner indicated.
Accordingly, a need exists for a non-recalibratable VHAD dial which can be zeroed after initial headlamp aiming, may easily be rendered non-recalibratable after the lamp has been properly aimed at the factory, conforms to the new NHTSA standards, is cost effective to assemble, and is easily installed and operated.